Seventy consecutive adult patients with acute myelogenous leukemia (AML), median age 44 years, received high-dose cytarabine (3 g/m2 every 12 hours for 12 doses) followed by daunorubicin (45 mg/m2 daily for three doses) for remission induction. A single, identical course was planned for postremission therapy. Complete remission (CR) was achieved in 63 patients (90%, 95% confidence interval [CI] 83% to 97%), 60 after a single course. Eight patients were selected to undergo elective bone marrow transplantation (BMT) during first CR. Of the remaining 55 patients, 40 (73%) underwent planned post-CR therapy; 15 patients did not, owing to early relapse, excessive toxicity from the induction chemotherapy, or refusal. Nineteen patients, including 13 who received planned post-CR therapy, remain in continuous CR at a median follow-up of 5.2 years (range 3.0 to 7.1 years). The 5-year actuarial leukemia- free survival was 30% (95% Cl, 19% to 42%) for all patients achieving CR and 32% (95% Cl, 19% to 47%) for the 40 patients who received the planned post-CR chemotherapy. Analysis of various putative prognostic factors for CR and overall and leukemia-free survival showed significance for a previous history of myelodysplasia, higher initial leukocyte counts, certain French-American-British (FAB) types, and certain abnormal karyotypes. None of these factors was consistently significant regarding the above parameters, although small patient numbers in certain analyses may have obscured significant associations. Myelosuppression was occasionally prolonged after remission induction and especially post-CR therapy. Severe cerebellar toxicity was observed in 13 patients; in 11 cases, this toxicity was fully reversible. Other serious complications were infrequent. Intensive chemotherapy with high- dose cytarabine and daunorubicin has substantial antileukemic activity in adult AML, and may represent an improvement over conventional therapy. Relapses were common, however, even in patients who received planned therapy, and substantial toxicity was observed. The optimum use of this regimen in AML remains to be determined.